Direct current (DC) machines are used today for many purposes, in particular in their modern form as electronically commutated motors (ECMs), since they combine a compact design with long service life and excellent positioning properties. This is true in particular of such machines in the power range from 5 to 500 W.
It is very advantageous in this context to control such DC machines using digital control elements such as microcontrollers or microprocessors, plus an associated program. The program is preferably designed so that it can control all the functions of the DC machine, e.g. commutation of current from one winding phase to the other, rotation speed regulation, rotation speed monitoring (is the direct current machine defective or jammed?), external communication via a data bus, or documentation of characteristic operating data of the DC machine, e.g. operating hours, maximum winding temperature attained, production date, factory number.
It is desirable in this context to make a DC machine of this kind versatile, i.e. the program plus hardware should make it possible to use a DC machine of this kind, and a device equipped with it, in many different ways. This is the case not least for one of the principal areas of application of such machines, namely the driving of fans.